Stabilized liquid ozone



United States Patent 3,126,607 STAEELIZED LEQUED GZQTNE .larnes S.Logan, Niagara Falls, and Arthur Roaldi, Lancaster, N341, assignors toWin Mathieson Chemical Corporation, a corporation of Virginia NoDrawing. Filed Jan. 30, 1958, Ser. No. 712,274 2 Claims. (Cl. 23--222)This invention relates to liquid ozone which is stable under conditionsof rapid evaporation.

zone, 0 molecular weight 48, is an unstable blue gas with a pungentcharacteristic odor and is generally encountered in dilute form inadmixture with air or oxygen. It has a melting point of 191.l C. and aboiling point of 111.9 C. At -111.9 C. ozone condenses to a dar. blueliquid. Ozone is customarily handled as a gas or in admixture withliquid oxygen. It is used commercially in the purification of drinkingWater, as a powerful oxidant in both organic and inorganic reactions andin the treatment of industrial wastes. It is also used for thedeodorization of air and sewage gases as well'as for the preservation offoods in cold storage. More recently, liquefied ozone has found utilityas an oxidant with rocket fuels.

(See U.S. Patent 2,704,274 for a discussion in some detail of this use.)The handling of liquid ozone during its.

preparation, storage, shipment and use has presented new problems sinceit is easily exploded as are concentrated ozone-oxygen mixtures (aboveabout 15 weight percent ozone), in either the liquid or vapor state.These explosions may be initiated by minute amounts of catalysts ororganic matter, shock, electric spark or sudden changes in temperature,pressure, etc. For example, any .hot spots in lines, valves, etc., in aliquid ozone handling system or any leaks in such a system could causerapid evaporation of the liquid ozone resulting in an explosion.

A It has now been found that liquid ozone can be rendered stable withrespect to initiation of an explosion under rapid evaporation conditionsby incorporating carbon tetrachloride therein. The amount of carbontetrachloride added to the ozone can vary widely but generally is fromabout 0.5 to 25 weight percent based on the ozone and preferably 15 to25 weight percent.

In order to evaluate the stability of the liquid ozone compositions ofthis invention a test procedure was devised which is as follows: Astandard vacuum line is used to condense, concentrate and supply ozonefor the test. A 10 mm. Pyrex tube, about 6 inches long'and sealed off atthe bottom, is attached to the line after evacuation and ozone isvaporized from a storage trap and condensed into the test tube which iscooled in a liquid oxygen bath. 'The ozone is purified by evacuation toremove any oxygen resulting from decomposition during transfer. Afteradding nitrogen gas to the tube up to atmospheric pressure, it ismanually removed from the oxygen bath and quickly placed in a waterbath. Theternperature of the latter determines the rate of boiling andis the criterion which determines efiectiveness. Two types of results,upon immersion of the tube into the water bath, have been 'ob- PatentedJune 9, 1964 Example I 3 grams of ozone were condensed into the tubemaintamed at 183 C. by the liquid oxygen bath. The liquid ozone waspurified by evacuation of the tube to remove any oxygen and the tube waspressured to atmospheric pressure with nitrogen. The tube was manuallyremoved from the liquid oxygen bath and quickly placed in an ice-slushbath (0 C.). The tube exploded violently.

Example 11 0.06 gram of carbon tetrachloride Was placed in the tube andthe tube was cooled to --183 C. by immersion in a liquid oxygen bath.Ozone, 0.3 gram, was then condensed on top of the CCh. After the tubewas brought to atmospheric pressure by the addition of nitrogen gas, itwas manually removed from the oxygen bath and quickly placed in a beakerof water maintained at C. Upon immersion of the tube in the water, arapid boiling of the ozone occurred with no explosion. It is apparentfrom this example that carbon tetrachloride is effective in preventingan explosion when ozone is vigorously boiled. The procedure of Example11 was twice repeated. using water baths maintained at 0 C. and C. Uponimmersion of the tube in the ice-slush bath, a rapid boiling of theozone occurred with no explosion, whilean explosion occurred uponimmersion of the tube in the 75 C. bath.

The claims:

1. -A liquid ozone composition consisting of liquid ozone and about 0.5to 25 weight percent based on the ozone of carbon tetrachloride.

2. A liquid ozone composition consisting of liquid ozone and about 0.5to 5 weight percent based on the ozone 0 carbon tetrachloride. V I

References Cited in the file of this patent v oTHER REFERENCES Cook etal.; Ind. and Eng. Chem.,'vo1. 48, No. 4, pp.

736-741, April 1956.

pages 20,22.

Thorp: Bibliography of- Ozone Technology, vol. 2, pages 30-47, John S.Swift Co., 1110., Chicago, Ill. 1955. f

Journal of American Rocket Society, December 1947,

1. A LIQUID OZONE COMPOSITION CONSISTING OF LIQUID OZONE AND ABOUT 0.5TO 25 WEIGHT PERCENT BASED ON THE OZONE OF CARBON TETRACHLORIDE.